Extracellular proteins play important roles in, among other things, the formation, differentiation and maintenance of multicellular organisms. The fate of many individual cells, e.g., proliferation, migration, differentiation, or interaction with other cells, is typically governed by information received from other cells and/or the immediate environment. This information is often transmitted by secreted polypeptides (for instance, mitogenic factors, survival factors, cytotoxic factors, differentiation factors, neuropeptides, and hormones) which are, in turn, received and interpreted by diverse cell receptors or membrane-bound proteins. These secreted polypeptides or signaling molecules normally pass through the cellular secretory pathway to reach their site of action in the extracellular environment.
Secreted proteins have various industrial applications, including as pharmaceuticals, diagnostics, biosensors and bioreactors. Most protein drugs available at present, such as thrombolytic agents, interferons, interleukins, erythropoietins, colony stimulating factors, and various other cytokines, are secretory proteins. Their receptors, which are membrane proteins, also have potential as therapeutic or diagnostic agents. Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. Examples of screening methods and techniques are described in the literature [see, for example, Klein et al., Proc. Natl. Acad. Sci. 93:7108-7113 (1996); U.S. Pat. No. 5,536,637)].
Membrane-bound proteins and receptors can play important roles in, among other things, the formation, differentiation and maintenance of multicellular organisms. The fate of many individual cells, e.g., proliferation, migration, differentiation, or interaction with other cells, is typically governed by information received from other cells and/or the immediate environment. This information is often transmitted by secreted polypeptides (for instance, mitogenic factors, survival factors, cytotoxic factors, differentiation factors, neuropeptides, and hormones) which are, in turn, received and interpreted by diverse cell receptors or membrane-bound proteins. Such membrane-bound proteins and cell receptors include, but are not limited to, cytokine receptors, receptor kinases, receptor phosphatases, receptors involved in cell-cell interactions, and cellular adhesin molecules like selectins and integrins. For instance, transduction of signals that regulate cell growth and differentiation is regulated in part by phosphorylation of various cellular proteins. Protein tyrosine kinases, enzymes that catalyze that process, can also act as growth factor receptors. Examples include fibroblast growth factor receptor and nerve growth factor receptor.
Membrane-bound proteins and receptor molecules have various industrial applications, including as pharmaceutical and diagnostic agents. Receptor immunoadhesins, for instance, can be employed as therapeutic agents to block receptor-ligand interactions. The membrane-bound proteins can also be employed for screening of potential peptide or small molecule inhibitors of the relevant receptor/ligand interaction.
Efforts are being undertaken by both industry and academia to identify new, native receptor or membrane-bound proteins. Many efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel receptor or membrane-bound proteins.
1. PRO1484
Adipose differentiation is accompanied by changes in cellular morphology, a dramatic accumulation of intracellular lipid and activation of a specific program of gene expression (Liang et al., J. Biol. Chem. 271:10697-10703 (1996)). Adipose complement-related protein is a protein whose expression is highly induced during adipocyte differentiation and which shares significant homology with subunits of complement factor C1q, collagen alpha 1(x) and the brain-specific facto cerebellin (Scherer et al., J. Biol. Chem. 270:26746-26749 (1995)). While the function of adipocyte complement-related protein is presently unknown, the tissue-specific expression thereof suggests that this protein functions as a novel signaling molecule for adipose tissue. As such, there is significant interest in identifying and characterizing novel polypeptides having homology to adipocyte complement-related protein. We herein describe the identification and characterization of novel polypeptides having homology to adipocyte complement-related protein, designated herein as PRO1484 polypeptides.
2. PRO4334
Plasma cell membrane glycoprotein PC-1 is of interest. The cloning of PC-1 is described in the art, i.e., see Buckley, et al., J. Biol. Chem., 265(29):17506-11 (1990) and WO9519570-A. WO9519570-A describes the human insulin receptor tyrosine kinase inhibitor PC-1. It is reported that PC-1 is useful in the diagnosis and treatment of diseases involving inappropriate insulin receptor tyrosine kinase inhibitor expression such as non-insulin dependent mellitus. Thus, proteins having homology to PC-1 are of interest.
3. PRO1122
It has been reported that the cytokine interleukin 17 (IL-17) stimulates epithelial, endothelial, and fibroblastic cells to secrete cytokines such as IL-6, IL-8, and granulocyte-colony-stimulating factor, as well as prostaglandin E2. Moreover, it has been shown that when cultured in the presence of IL-17, fibroblasts could sustain proliferation of CD34+ preferential maturation into neutrophils. Thus it has been suggested that IL-17 constitutes an early initiator of the T cell-dependent inflammatory reaction and/or an element of the cytokine network that bridges the immune system to hematopoiesis. See, Yao, et al., J. Immunol., 155(12):5483-5486 (1995); Fossiez, et al., J. Exp. Med., 183(6):2593-2603 (1996); Kennedy, et al., J. Interferon Cytokine Res., 16(8):611-617 (1996). Thus, proteins related to IL-17, including CTLA-8, which has been mistaken for IL-17 (see Kennedy, supra) are of interest.
4. PRO1889
E48 antigen protein is a cysteine-rich GPI-anchored membrane protein that belongs to the LY-6 family of human proteins (see, e.g., WO 96/35808). The E48 antigen serves as a marker for squamous cells, exhibits biological activity of cell-cell/cell-matrix adhesion and is a target for antibody-based immunotherapy. The amino acid sequence of the E48 antigen protein has previously been deduced from a cDNA clone which was obtained from a squamous cell carcinoma of the head and neck. As such, the E48 antigen serves as a potential target for the treatment of squamous cell cancer.
We herein describe the identification and characterization of novel polypeptides having homology to E48 antigen protein, designated herein as PRO1889 polypeptides.
5. PRO1890
The recognition of carbohydrates by lectins has been found to play an important role in various aspects of eukaryotic physiology. A number of different animal and plant lectin families exist, but it is the calcium dependent, or type C, lectins that have recently garnered the most attention. For example, the recognition of carbohydrate residues on either endothelial cells or leukocytes by the selectin family of calcium dependent lectins has been found to be of profound importance to the trafficking of leukocytes to inflammatory sites. Lasky, L., Ann. Rev. Biochem., 64 113-139 (1995). The biophysical analysis of these adhesive interactions has suggested that lectin-carbohydrate binding evolved in this case to allow for the adhesion between leukocytes and the endothelium under the high shear conditions of the vasculature. Thus, the rapid on rates of carbohydrate recognition by such lectins allows for a hasty acquisition of ligand, a necessity under the high shear of the vascular flow. The physiological use of type C lectins in this case is also supported by the relatively low affinities of these interactions, a requirement for the leukocyte rolling phenomenon that has been observed to occur at sites of acute inflammation. The crystal structures of the mannose binding protein (Weis et al., Science 254, 1608-1615 [1991]; Weis et al., Nature 360 127-134 [1992]) and E-selectin (Graves et al., Nature 367(6463), 532-538 [1994]), together with various mutagenesis analyses (Erbe et al., J. Cell. Biol. 119(1), 215-227 [1992]; Drickamer, Nature 360, 183-186 [1992]; Iobst et al., J. Biol. Chem. 169(22), 15505-15511 [1994]; Kogan et al., J. Biol. Chem. 270(23), 14047-14055 [1995]), is consistent with the supposition that the type C lectins are, in general, involved with the rapid recognition of clustered carbohydrates. Together, these data suggest that type C lectins perform a number of critical physiological phenomena through the rapid, relatively low affinity recognition of carbohydrates.
Given the obvious importance of the lectin proteins in numerous biological processes, efforts are currently being made to identify novel lectin proteins or proteins having sequence homology to lectin proteins. We herein describe the identification and characterization of novel polypeptides having homology to a lectin protein, designated herein as PRO1890 polypeptides.
6. PRO1887
Enzymatic proteins play important roles in the chemical reactions involved in the digestion of foods, the biosynthesis of macromolecules, the controlled release and utilization of chemical energy, and other processes necessary to sustain life. Enzymes have also been shown to play important roles in combating various diseases and disorders. For example, liver carboxylesterases have been reported to assist in sensitizing human tumor cells to the cancer prodrugs. Danks et al., report that stable expression of the cDNA encoding a carboxylesterase in Rh30 human rhabdomyosarcoma cells increased the sensitivity of the cells to the CPT-11 cancer prodrug 8.1-fold. Cancer Res. (1998) 58(1):20-22. The authors propose that this prodrug/enzyme combination could be exploited therapeutically in a manner analogous to approaches currently under investigation with the combinations of ganciclovir/herpes simplex virus thymidine kinase and 5-fluorocytosine/cytosine deaminase. van Pelt et al. demonstrated that a 55 kD human liver carboxylesterase inhibits the invasion of Plasmodium falciparum malaria sporozoites into primary human hepatocytes in culture. J Hepatol (1997) 27(4):688-698.
Carboxylesterases have also been found to be of importance in the detoxification of drugs, pesticides and other xenobiotics. Purified human liver carboxylesterases have been shown to be involved in the metabolism of various drugs including cocaine and heroin. Prindel et al. describe the purification and cloning of a broad substrate specificity human liver carboxylesterase which catalyzes the hydrolysis of cocaine and heroin and which may play an important role in the degradation of these drugs in human tissues. J. Biol. Chem. (1997) 6:272(23):14769-14775. Brzenzinski et al. describe a spectrophotometric competitive inhibition assay used to identify drug or environmental esters that are metabolized by carboxylesterases. Drug Metab Dispos (1997) 25(9):1089-1096.
As additional background information on carboxylesterases, Kroetz et al. (Biochemistry, (1993) 32(43):11606-17) reported the cDNA cloning and characterization of human liver carboxylesterases. Aida et al. (Biochim Biophys Acta (1993) 1174(1):72-4) reported the cDNA cloning and characterization of a male-predominant carboxylesterase in mouse liver carboxylesterases.
In light of the important physiological roles played by carboxylesterases, efforts are being undertaken by both industry and academia to identify new, native carboxylesterase homologs. We herein describe the identification and characterization of a novel polypeptide having homology to carboxylesterase.
7. PRO1785
Antioxidant enzymes are thought to play a crucial role in the survival of the parasite, Schistosoma mansoni, during its migration through the tissues of a definitive host. Recently, one such enzyme, glutathione peroxidase was cloned. Roche, et al., Gene, 138:149-152 (1994), accession number GSHC_SCHMA. Glutathione perxodiases are further described in FR2689906-A. Thus, glutathione peroxidases, and the nucleic acids which encode them are useful as diagnostic reagents, vaccines and in assays to find modulators of antioxidant enzymes.
8. PRO4353
Semaphorins comprise a large family of proteins implicated in axonal guidance during development. Semaphorin Y may be used to inhibit peripheral nerve growth. Semaphorin Z is useful as a central nerve extension inhibitor. Semaphorin Z inhibitors can be used as promoters of central nerve regeneration. Thus semaphorins and regulators of semaphorins are of great interest. Kikuchi, et al., Brain Res Mol Brain Res., 51(1-2):229-37 (1997); Shoji, et al., Development, 125(7):1275-83 (1998).
9. PRO4357
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4357 polypeptides.
10. PRO4405
Efforts are being undertaken by both industry and academia to identify new, native transmembrane receptor proteins. Many efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel transmembrane receptor proteins. We herein describe the identification and characterization of novel transmembrane polypeptides, designated herein as PRO4405 polypeptides.
11. PRO4356
Glycosylphosphatidylinositol (GPI) anchored proteoglycans are generally localized to the cell surface and are thus known to be involved in the regulation of responses of cells to numerous growth factors, cell adhesion molecules and extracellular matrix components. The metastasis-associated GPI-anchored protein (MAGPIAP) is one of these cell surface proteins which appears to be involved in metastasis. Metastasis is the form of cancer wherein the transformed or malignant cells are traveling and spreading the cancer from one site to another. Therefore, identifying the polypeptides related to metastasis and MAGPIAP is of interest.
12. PRO4352
Cadherins are a large family of transmembrane proteins. Cadherins comprise a family of calcium-dependent glycoproteins that function in mediating cell-cell adhesion in virtually all solid tissues of multicellular organisms. At least cadherins 1-13 as well as types B, E, EP, M, N, P and R have been characterized. Among the functions cadherins are known for, with some exceptions, cadherins participate in cell aggregation and are associated with cell-cell adhesion sites. Recently, it has been reported that while all cadherins share multiple repeats of a cadherin specific motif believed to correspond to folding of extracellular domains, members of the cadherin superfamily have divergent structures and, possibly, functions. In particular it has been reported that members of the cadherin superfamily are involved in signal transduction. See, Suzuki, J. Cell Biochem., 61(4):531-542 (1996). Cadherins are further described in Tanihara, et al., J. Cell Sci., 107(6):1697-1704 (1994), Aberle, et al., J. Cell Biochem., 61(4):514-523 (1996), Obata, et al., Cell Adhes. Commun., 6(4):323-33 (1998) and Tanihara, et al., Cell Adhes. Commun., 2(1):15-26 (1994).
Protocadherins are members of the cadherin superfamily which are highly expressed in the brain. In some studies, protocadherins have shown cell adhesion activity. See, Sano, et al., EMBO J., 12(6):2249-2256 (1993). However, studies have also shown that some protocadherins, such as protocadherin 3 (also referred to as Pcdh3 or pc3), do not show strong calcium dependent cell aggregation activity. See, Sago, et al., Genomics, 29(3):631-640 (1995) for this study and further characteristics of Pcdh3. Molecules related to pc3 are thus of great interest. Also of great interest is the subtype of desmosomal cadherin described in Koch, et al., Differentiation, 47(1):29-36 (1991).
Of particular interest are proteins having a sequence with homology to that described in Amagai, et al., Cell, 67(5):869-77 (1991). This study describes antibodies against a novel epithelial cadherin in pemphigus vulgaris, a disease of cell adhesion. Also of interest are full-length cadherins. Additionally, proteins having homology to the fat tumor suppressor gene which are novel cadherins are of interest.
13. PRO4380
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4380 polypeptides.
14. PRO4354
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4354 polypeptides.
15. PRO4408
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4408 polypeptides.
16. PRO5737
Interleukin-1 refers to two proteins (IL-1α and IL-1β) which play a key role early in the inflammatory response (for a review, see Dinarello, Blood, 87: 2095-2147 (1996) and references therein). Both proteins are made as intracellular precursor proteins which are cleaved upon secretion to yield mature carboxy-terminal 17 kDa fragments which are biologically active. In the case of IL-1β, this cleavage involves an intracellular cysteine protease, known as ICE, which is required to release the active fragment from the inactive precursor. The precursor of IL-1α is active.
These two proteins act by binding to cell surface receptors found on almost all cell types and triggering a range of responses either alone or in concert with other secreted factors. These range from effects on proliferation (e.g. fibroblasts, T cells) apoptosis (e.g. A375 melanoma cells), cytokine induction (e.g. of TNF, IL-1, IL-8), receptor activation (e.g. E-selectin), eicosanoid production (e.g. PGE2) and the secretion of degradative enzymes (e.g. collagenase). To achieve these effects, IL-1 activates transcription factors such as NF-KB and AP-1. Several of the activities of IL-1 action on target cells are believed to be mediated through activation of kinase cascades that have also been associated with cellular stresses, such as the stress activated MAP kinase JNK/SAPK and p38.
A third member of the IL-1 family was subsequently discovered which acts as a natural antagonist of IL-1α and IL-1β by binding to the IL-1 receptor but not transducing an intracellular signal or a biological response. The protein is called IL-1Ra (for IL-1 receptor antagonist) or IRAP (for IL-1 receptor antagonist protein). At least three alternatively spliced forms of IL-1Ra exist: one encodes secreted protein, and the other two encode intracellular proteins. IL-1α, IL-1β and IL-1Ra exhibit approximately 25-30% sequence identity with each other and share a similar three dimensional structure consisting of twelve β-strands folded into a β-barrel, with an internal thrice repeated structural motif.
There are three known IL-1 receptor subunits. The active receptor complex consists of the type I receptor and IL-1 accessory protein (IL-1RAcP). The type I receptor is responsible for binding of the IL-1α, IL-1β and IL-1Ra ligands, and is able to do so in the absence of the IL-1RAcP. However, signal transduction requires the interaction of IL-1α or IL-1β with the IL-1 RAcP. IL-1 Ra does not interact with the IL-1RAcP and hence cannot induce signal transduction. A third receptor subunit, the type II receptor, binds IL-1α and IL-1β but cannot transduce signal due its lack of an intracellular domain. Instead, the type II receptor either acts as a decoy in its membrane bound form or as an IL-1 antagonist in a processed, secreted form, and hence inhibits IL-1 activity. The type II receptor weakly binds to IL-1Ra.
Many studies using IL-1Ra, soluble IL-1R derived from the extracellular domain of the type I IL-1 receptor, antibodies to IL-1α or IL-1β, and transgenic knockout mice for these genes have shown that IL-1 plays a role in a number of pathophysiologies (for a review, see Dinarello, Blood, 87: 2095-2147 (1996)). For example, IL-1Ra has been shown to be effective in animal models of septic shock, rheumatoid arthritis, graft-versus-host disease (GVHD), stroke, cardiac ischemia, psoriasis, inflammatory bowel disease, and asthma. In addition, IL-1Ra has demonstrated efficacy in clinical trials for rheumatoid arthritis and GVHD, and is also in clinical trials for inflammatory bowel disease, asthma and psoriasis.
More recently, interleukin-18 (IL-18) was placed in the IL-1 family (for a review, see Dinarello et al, J. Leukocyte Biol., 63: 658-664 (1998)). IL-18 shares the β-pleated, barrel-like form of IL-1α and IL-1β. In addition, IL-18 is the natural ligand for the IL-1 receptor family member formerly known as IL-1R-related protein (IL-1Rrp) (now known as the IL-18 receptor (IL-18R)). IL-18 has been shown to initiate the inflammatory cytokine cascade in a mixed population of peripheral blood mononuclear cells (PBMCs) by triggering the constitutive IL-18 receptors on lymphocytes and NK cells, inducing TNF production in the activated cells. TNF, in turn, stimulates IL-1 and IL-8 production in CD14+ cells. Because of its ability to induce TNF, IL-1, and both C—C and C—X—C chemokines, and because IL-18 induces Fas ligand as well as nuclear translocation of nuclear factor 6B (NF-6B), IL-18 ranks with other pro-inflammatory cytokines as a likely contributor to systemic and local inflammation.
17. PRO4425
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4425 polypeptides.
18. PRO5990
The secretogranin proteins (e.g. secretogranin I and II) are found in secretory granules in a variety of endocrine cells and neurons. Schimmel, A. et al., FEBS Lett. 314(3):375-80 (1992); Gerdes, H. H. et al., J. Biol. Chem. 264(20): 12009-15. A possible function of the secretogranin proteins is the packaging of secretory products, including regulatory peptides. Chanat, E. et al., FEBS Lett. 351(2):225-30 (1994); Rosa, P. et al., J. Cell. Biol. 101(5):1999-2011 (1985); Gorr, S. U. et al., Am. J. Physiol. 257(2):E247-54 (1989). Secretogranins have been successfully used as biological markers in a number of contexts. For example, secretogranin II has gained importance as an immunohistochemical marker for endocrine neoplasms. See Fischer-Colbrie, R. et al., J. Biol. Chem. 265(16):9208-13 (1990). Eder et al. found that the ratio of secretogranin II to chromogranins was remarkably constant within patient populations, and suggest that the ratio may be used as a parameter to standardize CSF levels of other peptides, such as neuropeptides. Eder, U., et al., J. Neural Transm., 105(1):39-51 (1998).
We herein describe the identification and characterization of novel polypeptides having sequence similarity to secretogranin, designated herein as PRO5990 polypeptides.
19. PRO6030
Efforts are being undertaken by both industry and academia to identify new, native transmembrane receptor proteins. Many efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel transmembrane receptor proteins. We herein describe the identification and characterization of novel transmembrane polypeptides, designated herein as PRO6030 polypeptides.
20. PRO4424
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4424 polypeptides.
21. PRO4422
Lysozyme is a protein which is widely distributed in several human tissues and secretions including milk, tears and saliva. It has been demonstrated to hydrolyze linkages between N-acetylglucosamines. It has been demonstrated to be an inhibitor of chemotaxis and of the production of toxic oxygen free radicals and may also have some role in the calcification process. As such, there is substantial interest in identifying novel polypeptides having homology to lysozyme. Nakano and Graf, Biochim. Biophys Acta, 1090(2):273-6 (1991).
22. PRO4430
Efforts are being undertaken by both industry and academia to identify new, native secreted proteins. Many of these efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel secreted proteins. We herein describe the identification and characterization of novel secreted polypeptides, designated herein as PRO4430 polypeptides.
23. PRO4499
Efforts are being undertaken by both industry and academia to identify new, native transmembrane receptor proteins. Many efforts are focused on the screening of mammalian recombinant DNA libraries to identify the coding sequences for novel transmembrane receptor proteins. We herein describe the identification and characterization of novel transmembrane polypeptides, designated herein as PRO4499 polypeptides.